Yodi went there to kill him. Does not matter who else was there. Yodi knew what he was going to get himself into.

 

Yodi lost and went running away. Yodi can 'justify' himself all he wants. In the end he lost, as it was fortold, it was his destiny.

Despite the fact I believe palpatine to have the edge force wise. I have no doubts Yoda was winning the fight. It seemed so clear to me, one of the most fatal flaws of the sith was hurting palpatines attempts, his arrogance and overconfidence was making him underestimate Yoda. The best example is when Yoda leaps onto palpatines pod, palpatine shocks Yoda's lightsaber from his hand and Attcks him with a fury of force lightning. Seeing Yoda struggle against the torrent, he grins manically at yoda believing he has won, only to gasp in horror as Yoda quickly over powers his attck and in a massive explosion of the force Yoda and palpatine are sent flying, Yoda falls to the ground, while palpatine clings to a pod laughing at the tiny Jedi. Palpatine himself believes Yoda to be more capable than he, as he even tries to escape from the valiant Jedi before the fight had begun. Had palpatine failed to grab hold of the pod rails I think the outcome may have been very different.